IP packets are like a C struct that only have 4 bytes allocated per address. If you want to have more space, you need to change that struct, and that's what IPv

IP packets are like a C struct that only have 4 bytes allocated per address. If you want to have more space, you need to change that struct, and that's what IPv6 does. Together with a new Ethertype so the different structs can be reliably differentiated.